1. Field
The present invention relates to wireless communication systems, and more particularly, to a method and apparatus for user equipment (UE) to perform the cell selection and re-selection, using PMAX parameters.
2. Description of Related Art
In order to meet the increase in the demand for wireless data traffic after the commercialization of 4G communication systems, considerable effort has been made to develop pre-5G communication systems or improved 5G communication systems. In order to achieve a high data transmission rate, 5G communication systems are being developed to be implemented in a band of extremely high frequency, or millimeter wave (mmWave), e.g., a band of 60 GHz. This is one reason why ‘5G communication systems’ or ‘pre-5G communication systems’ are called ‘beyond 4G network communication systems’ or ‘post LTE systems.’ In order to reduce the occurrence of stray electric waves in a band of extremely high frequency energy and to increase the transmission distance of electric waves in 5G communication systems, various technologies being explored, for example: beamforming, massive MIMO, Full Dimensional MIMO (FD-MIMO), array antennas, analog beam-forming, large scale antennas, etc. In order to improve system networks for 5G communication systems, various technologies have been developed, e.g.,: evolved small cell, advanced small cell, cloud radio access network (cloud RAN), ultra-dense network, Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), interference cancellation, etc. In addition, for 5G communication systems, other technologies have been developed, e.g., Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), as Advanced Coding Modulation (ACM), Filter Bank Multi Carrier (FBMC), non-orthogonal multiple access (NOMA), sparse code multiple access (SCMA), etc.
The Internet has evolved from a human-based connection network, where humans create and consume information; to the Internet of Things (IoT) where distributed configurations, such as objects, exchange information with each other to process the information. The technology related to the IoT is starting to be combined with, for example, a technology for processing big data through connection with a cloud server, and this is called an Internet of Everything (IoE) technology. In order to manifest the IoT, various technical components are required, such as, a sensing technology, wired/wireless communication and network infra technology, a service interfacing technology, a security technology, etc. In recent years, a sensor network for connecting objects, Machine to Machine (M2M), Machine Type Communication (MTC), etc. have been researched. Under the IoT environment, intelligent Internet Technology (IT) services may be provided to collect and analyze data obtained from objects connected to each other and thus to create new value for human life. As existing IT technologies are fused and combined with various industries, the IoT may also be applied within various fields, such as: smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, health care, smart home appliances, high quality medical services, etc.
To this end, various attempts have been made to apply 5G communication systems to the IoT. For example, various technologies related to sensor networks, Machine to Machine (M2M), Machine Type Communication (MTC), etc., have been implemented by beam-forming, MIMO, array antenna, etc., as 5G communication technology. The application of the cloud RAN as a big data processing technology described above may be an example of a hybrid of 5G technology and IoT technology.
As such, in order to meet the increase in the demand for wireless data traffic, research has been undertaken to develop communication systems in various technical fields. Examples of the communication systems are device to device (D2D) communication, a carrier aggregation system for operating a number of cells, a multiple antenna system using large scale antennas, etc.